| From 1e259e0a9982078896f3404240096cbea01daca4 Mon Sep 17 00:00:00 2001 |
| From: Frederic Weisbecker <fweisbec@gmail.com> |
| Date: Sun, 28 Feb 2010 20:51:15 +0100 |
| Subject: hw-breakpoints: Remove stub unthrottle callback |
| |
| From: Frederic Weisbecker <fweisbec@gmail.com> |
| |
| commit 1e259e0a9982078896f3404240096cbea01daca4 upstream. |
| |
| We support event unthrottling in breakpoint events. It means |
| that if we have more than sysctl_perf_event_sample_rate/HZ, |
| perf will throttle, ignoring subsequent events until the next |
| tick. |
| |
| So if ptrace exceeds this max rate, it will omit events, which |
| breaks the ptrace determinism that is supposed to report every |
| triggered breakpoints. This is likely to happen if we set |
| sysctl_perf_event_sample_rate to 1. |
| |
| This patch removes support for unthrottling in breakpoint |
| events to break throttling and restore ptrace determinism. |
| |
| Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> |
| Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> |
| Cc: K.Prasad <prasad@linux.vnet.ibm.com> |
| Cc: Paul Mackerras <paulus@samba.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| arch/x86/kernel/hw_breakpoint.c | 5 ----- |
| kernel/hw_breakpoint.c | 1 - |
| 2 files changed, 6 deletions(-) |
| |
| --- a/arch/x86/kernel/hw_breakpoint.c |
| +++ b/arch/x86/kernel/hw_breakpoint.c |
| @@ -531,8 +531,3 @@ void hw_breakpoint_pmu_read(struct perf_ |
| { |
| /* TODO */ |
| } |
| - |
| -void hw_breakpoint_pmu_unthrottle(struct perf_event *bp) |
| -{ |
| - /* TODO */ |
| -} |
| --- a/kernel/hw_breakpoint.c |
| +++ b/kernel/hw_breakpoint.c |
| @@ -489,5 +489,4 @@ struct pmu perf_ops_bp = { |
| .enable = arch_install_hw_breakpoint, |
| .disable = arch_uninstall_hw_breakpoint, |
| .read = hw_breakpoint_pmu_read, |
| - .unthrottle = hw_breakpoint_pmu_unthrottle |
| }; |
